1. Field
The present disclosure relates generally to sensors and, in particular, to optical sensors. Still more practically, the present disclosure relates to a method and apparatus for an optical sensor for detecting multiple types of parameters.
2. Background
Many different types of sensors may be used to detect a physical quantity and generate a signal with information about the physical quantity detected. The physical quantity may also be referred to as a parameter. For example, electrical sensors have been commonly used to detect parameters, such as temperature, pressure, and other types of physical quantities. For example, an electrical sensor may be used to detect temperature and pressure within an interior of the fuel tank of an aircraft.
When electrical sensors are used within a fuel tank, wires connecting the sensors to power and other devices in the aircraft extend into the fuel tank through openings formed in the fuel tank. These openings are sealed to prevent fuel from exiting the fuel tank. In detecting parameters such as fuel level, temperature, pressure, and other parameters, wires are used for each of the types of sensors located within the fuel tank.
With the use of electrical sensors, challenges with respect to shielding and grounding are present. Providing shielding for sensors such that the sensors may operate in a desired manner without causing an undesired condition in the fuel tank is desirable but challenging at times. These challenges increase with the use of composite materials. For example, when a fuel tank is formed from a composite material, shielding is more limited as compared to fuel tanks formed of metal materials. With a composite fuel tank, the inherent shielding and protection of a metal wall in a metal fuel tank is reduced or unavailable. As a result, additional systems are needed for a desired use and operation of an electrical sensor system.
Further, the size of electrical sensors may be larger than desired. For example, a capacitive sensor for detecting a level fuel in the fuel tank may be more complex than desired.
Issues with the use of electrical sensors may also be present for other locations in aircraft. As an example of an issue with respect to the use of electrical sensors in an engine of an aircraft, the heat generated by the engine of an aircraft may present challenges with respect to electrical sensors operating with a desired level of performance.
As a result, the space by the electrical sensors and associated devices, installation time, and other factors may be greater than desired. Therefore, it would be desirable to have a method and apparatus that takes into account at least some of the issues discussed above, as well as other possible issues.